noun

- Mathematics. a theoretical proposition, statement, or formula embodying something to be proved from other propositions or formulas.
- a rule or law, especially one expressed by an equation or formula.
- Logic. a proposition that can be deduced from the premises or assumptions of a system.
- an idea, belief, method, or statement generally accepted as true or worthwhile without proof.

noun

- maths logic a statement or formula that can be deduced from the axioms of a formal system by means of its rules of inference

n.1550s, from Middle French théorème, from Late Latin theorema, from Greek theorema “spectacle, speculation,” in Euclid “proposition to be proved,” from theorein “to consider” (see theory). n.

- An idea that is demonstrably true or is assumed to be so.
- A mathematical proposition that has been or is to be proved on the basis of explicit assumptions.

- A mathematical statement whose truth can be proved on the basis of a given set of axioms or assumptions.

A statement in mathematics that is not a basic assumption, such as an axiom, but is deduced (see deduction) from basic assumptions.